arm_q7_to_q15.c

00001 /* ----------------------------------------------------------------------
00002  * Project:      CMSIS DSP Library
00003  * Title:        arm_q7_to_q15.c
00004  * Description:  Converts the elements of the Q7 vector to Q15 vector
00005  *
00006  * $Date:        27. January 2017
00007  * $Revision:    V.1.5.1
00008  *
00009  * Target Processor: Cortex-M cores
00010  * -------------------------------------------------------------------- */
00011 /*
00012  * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
00013  *
00014  * SPDX-License-Identifier: Apache-2.0
00015  *
00016  * Licensed under the Apache License, Version 2.0 (the License); you may
00017  * not use this file except in compliance with the License.
00018  * You may obtain a copy of the License at
00019  *
00020  * www.apache.org/licenses/LICENSE-2.0
00021  *
00022  * Unless required by applicable law or agreed to in writing, software
00023  * distributed under the License is distributed on an AS IS BASIS, WITHOUT
00024  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00025  * See the License for the specific language governing permissions and
00026  * limitations under the License.
00027  */
00028 
00029 #include "arm_math.h"
00030 
00031 /**
00032  * @ingroup groupSupport
00033  */
00034 
00035 /**
00036  * @addtogroup q7_to_x
00037  * @{
00038  */
00039 
00040 
00041 
00042 
00043 /**
00044  * @brief Converts the elements of the Q7 vector to Q15 vector.
00045  * @param[in]       *pSrc points to the Q7 input vector
00046  * @param[out]      *pDst points to the Q15 output vector
00047  * @param[in]       blockSize length of the input vector
00048  * @return none.
00049  *
00050  * \par Description:
00051  *
00052  * The equation used for the conversion process is:
00053  *
00054  * <pre>
00055  *  pDst[n] = (q15_t) pSrc[n] << 8;   0 <= n < blockSize.
00056  * </pre>
00057  *
00058  */
00059 
00060 
00061 void arm_q7_to_q15(
00062   q7_t * pSrc,
00063   q15_t * pDst,
00064   uint32_t blockSize)
00065 {
00066   q7_t *pIn = pSrc;                              /* Src pointer */
00067   uint32_t blkCnt;                               /* loop counter */
00068 
00069 #if defined (ARM_MATH_DSP)
00070   q31_t in;
00071   q31_t in1, in2;
00072   q31_t out1, out2;
00073 
00074   /* Run the below code for Cortex-M4 and Cortex-M3 */
00075 
00076   /*loop Unrolling */
00077   blkCnt = blockSize >> 2U;
00078 
00079   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
00080    ** a second loop below computes the remaining 1 to 3 samples. */
00081   while (blkCnt > 0U)
00082   {
00083     /* C = (q15_t) A << 8 */
00084     /* convert from q7 to q15 and then store the results in the destination buffer */
00085     in = *__SIMD32(pIn)++;
00086 
00087     /* rotatate in by 8 and extend two q7_t values to q15_t values */
00088     in1 = __SXTB16(__ROR(in, 8));
00089 
00090     /* extend remainig two q7_t values to q15_t values */
00091     in2 = __SXTB16(in);
00092 
00093     in1 = in1 << 8U;
00094     in2 = in2 << 8U;
00095 
00096     in1 = in1 & 0xFF00FF00;
00097     in2 = in2 & 0xFF00FF00;
00098 
00099 #ifndef ARM_MATH_BIG_ENDIAN
00100 
00101     out2 = __PKHTB(in1, in2, 16);
00102     out1 = __PKHBT(in2, in1, 16);
00103 
00104 #else
00105 
00106     out1 = __PKHTB(in1, in2, 16);
00107     out2 = __PKHBT(in2, in1, 16);
00108 
00109 #endif
00110 
00111     *__SIMD32(pDst)++ = out1;
00112     *__SIMD32(pDst)++ = out2;
00113 
00114     /* Decrement the loop counter */
00115     blkCnt--;
00116   }
00117 
00118   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
00119    ** No loop unrolling is used. */
00120   blkCnt = blockSize % 0x4U;
00121 
00122 #else
00123 
00124   /* Run the below code for Cortex-M0 */
00125 
00126   /* Loop over blockSize number of values */
00127   blkCnt = blockSize;
00128 
00129 #endif /* #if defined (ARM_MATH_DSP) */
00130 
00131   while (blkCnt > 0U)
00132   {
00133     /* C = (q15_t) A << 8 */
00134     /* convert from q7 to q15 and then store the results in the destination buffer */
00135     *pDst++ = (q15_t) * pIn++ << 8;
00136 
00137     /* Decrement the loop counter */
00138     blkCnt--;
00139   }
00140 
00141 }
00142 
00143 /**
00144  * @} end of q7_to_x group
00145  */
00146